Table of Contents
ISRN Renewable Energy
Volume 2012, Article ID 987904, 8 pages
Research Article

Sensitivity Analysis for the Encaged Turbine Concept in Oscillating Water Column Plants

Thermal Engines Laboratory, Department of Mechanical Engineering and Aeronautics, Polytechnic School, University of Patras, 26500 Patras, Achaia, Greece

Received 31 October 2012; Accepted 2 December 2012

Academic Editors: H. Ramos and S. Senthilarasu

Copyright © 2012 Demos P. Georgiou et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Oscillating water column plants are one of the most popular wave energy device types. Prototype OWC units have been operating in various parts of the world since the mid-1980s and such developers have more field experience of this technology than any other relevant plant. The most common turbine used is the self-rectifying Well's turbine which has a rather low peak efficiency if compared to other designs but was preferred in terms of its simplicity and cycle performance. The present study exploits the merits of a new concept for the power extraction process, that of an encaged turbine for OWC plants, which allows conventional high-efficiency turbines to be employed in such plants. This is achieved by guiding the pressurized air into a sequence of three chambers, creating a unidirectional closed air circuit through the turbine. A theoretical model is deployed simulating the operation of the plant and a sensitivity analysis is carried out for the design and working parameters. Results indicate that the power extraction efficiency may exceed the 50% level in a real plant.